For any topical compound to be effective, including AHA, it must penetrate into the skin where it can act on living cells.

AHAs with greater bioavailability appear to have deeper dermal effects. Glycolic acid, lactic acid, and citric acid, on topical application to photodamaged skin, have been shown to produce increased amounts of mucopolysaccharides and collagen and increased skin thickness without detectable inflammation, as monitored by skin biopsies.